Electric switch operating mechanism



W. K. RANKIN ELECTRIC SWITCH OPERATING MECHANISI Aug. 23,' 1932.

' Filed Nov. 26, 1929 Inventor-n William K. Rankin,

Patented Aug. 23, 1932 UNITED .STATES PATENT OFFICE WILLIAMk xs orEANDSDOWNE PEN,NsYLvaNJLA,l lAss'IGNoR 'ro GENERAL ELECTRIC 'ColumnaCORPORATION or NEw Yom:

f ELECTRIC SWITCH OPERATING MECHANISM Application area Number 26,1929.-semi No.'.4o9,aea.

My invention relates to hydraulic operating mechanism, and moreparticularly to operating mechanism for circuit breakers having largeinterrupting capacities wherein the 5 operating means for closing thebreaker musty overcome repellent forces during closing movement thereof.In circuit breakers of comparatively large size and interruptingcapacity it is desirable 10 that the movable contact structure oftheclosing thek switch is ineffective to overcome' the aforesaid repellentforces,fthe switch may I6 not only remain open, but' arcing between thecontacts may, as in the case of oil switches forY example, causedestruction of the switch. y

It is a principal objectof my invention to provide an improved electricswitch operatau ing mechanism r'which shall .be reliable and and simple4and rugged l rcenter prevent any fluid beingv carried bef positive inroperation in construction.

f It is a further object of my invention to provide hydraulic operatingmeans for a c ircuit breaker of large interrupting capac1ty arranged sothat a switch actuating member may be moved towards its closed circuitpoj sition at a substantially constant or uniform speed by yfluidpressure notwithstanding the existence or variations in magnitude offorces opposing said movement.v

It is a further object of my invention to provide hydraulic operating'means'v for effectin g closure of switch mechanism wherein the kineticenergy' of rotation of a flywheel is effective to cause a substantiallyconstant or uniformdischarge of fluid formoving at a substantiallyconstant or uniform'rate an operatingv member coacting with said mech-k50 amsm.

' -My invention will be morefully set forthl in thek followingdescription referring to the accompanying drawing, and the features ofnovelty which characterize my invention will n,

be pointed' out with particularity in the claims annexed toand forming apart of this specification.

v Referring to the drawing, thesingle fig-r' ure thereof illustrates anelevational view, partly in section, of a hydraulic operating mechanismfor a circuit breaker system;

yA tank orfiuid reservoir 1 is provided containing a suitable hydraulicmedium 2 such tas oil, for example. Disposed within the reservoir is astructure 3 for defining fluid pas-k sages and for serving as mountingand guid` ing means'for elements acting upon or acted upon by the fluidtraversing s aid passages. The structure 3 forms a main passage 4, atone" endof which is disposed a: source of luid pressure or pump ofsuitable character, as a gear pump comprising a driving gear 5 andy adriven gear' (not shown) meshed therewith.

for urotation withina pump casing, in cornmunication with the fluid inthe main part of the reservoir'.y The gear pumpmay be of the usualwellknown type wherein the gear teeth pickupl the liquid and' carry itraround in the spaces between the teeth, the pum cas' ing rformingtherewithaluid-tight joint. The teeth lof the two gears meshing'at theshall be capable-of discharging luidat ak rate corresponding to itsoperating speed.

That is, if the speed of the pump ismain tained constantthe yrate ofiluid discharge from the pump islikewise constant. At the opposite endof passage 4 there is disposed ar valve 6 adapted toseat at 7 forpreventingv flow of the fluid 'from the lpassage into the' main partofthe reservoirthroughthe ports 8. An" operating member, comprising apiston 9 and a pistonv rod 9', is mounted for reciprocal movement withina cylindrical casing 10, which isin open communication at its' lowerendwiththe passage 4. The cylindri- CTI cal casing 10 is provided withthe exhaust ports or openings 11 in communication with the reservoir forbypassing the fluid acting upon the piston 9 when the lower end thereofhas uncovered the exhaust ports.

lVhen the valve 6 is closed actuation of the Junio 5 serves to forcefluid from the main l part of the reservoir into the passage 4, now

closed at its opposite end, thereby exerting fluid pressure on thepiston 9 tending to force it upwardly until the exhaust ports 11 havebeen uncovered. v

The operating member may serve to actuate suitable mechanisnnas forexample circuit breaker mechanism used for switches of the oil breaktype, through a switch actuating member 12. In circuit breakers of theabove described character it is desirable that the closing operation beeffected with sufficient force to insure closing at a substantiallyconstant or uniform speed. Due, however, to the fact that there areoften repellent forces set up by the magnetic forces of the currentagainst which the switch is to be closed, and moreover since thesecurrents in the case of short circuit or overload may vary in magnitudewithin a wide range, it will be apparent that considerable difficultymaybe experienced in effecting closing of the circuit breaker at asubstantially constant or uniform speed in the event that provision isnot made for overcoming these resisting forces.

The hydraulic operating member 9 and the switch actuating member 12 maybe interconnected in any suitable manner to provide the usual trip freeaction in case of predetermined overload or short circuit, and in thepresent instance the interconnecting means comprises a bell crank 13pivotally mounted as at 13 to a frame structure 14 secured to or mountedupon the reservoir 1. One arm of the bell crank 13 is connected as at 15to the switch actuating member 12 and the other arm is connected as at16 to one end of a toggle 17. The center or thrust-receiving portion ofthe toggle 18 is adapted to be engaged by the upper end of the pistonrod 9', the other end of thetoggle being connected as at 19 to a link 20pivoted at its opposite end to a stationaryT lug or support 21. For thepurpose of maintaining the pivot 19 of the toggle stationary so thatupward movement of the piston rod 9 may extend the toggle to rotate thebell crank 13 in a counter clockwise direction thereby effecting closingmovement of the switch actuating member'12, there is provided alatcliing member 22 pivoted at one end to the frame 14 and having a hookportion 23 at its opposite or free end for engaging the pivot 19 forminga part of the link 20 for restraining it from clockwise movement. Itwill be apparent, therefore, that disengagement of the latch from thepivot 19 of the toggle permits the link 2O to move in a clockwisedirection thereby allowing immediate collapse of the toggle and returnof the bell crank and the switch actuating member to their originalpositions as illustrated. In other words, the latch 22 permits what isknown as trip-free action, and to accomplish this end the usual trippingmagnet 24 is adapted, when energized a predetermined extent, to engageone arm of a bell crank 25 pivoted as at 26 to the frame 14, and rotateit in a clockwise direction. This movement lifts the link 27, which isconnected to the other arm of the bell crank 25 and to the latch 22, tocause counter clockwise movement of the latch 22suticiently to disengageit from the toggle.

As previously stated, it is desirable that the hydraulic operatingmember be actedv upon by suflicient force to cause closing of the switchactuating member at a substantially constant speed. To this end therotatable element of the pump 5 is operated by a sha-ft 28 driven bysuitable motive means, as a motor 29, the driving shaft 28 having fixedthereon a comparatively large and massive rotatable member, as aflywheel 30. Or, the rotor of the motor itself, if of the rotating fieldtype, may comprise the rotatable mass. The motor 29 may be energizedfrom any suitable source of supply 31, and may be controlled by amanually operated switch 32 and a limit switch 33 connected to anysuitable part of the switch actuating mechanism, as the bell crank 13and insulated therefrom as at 33. When the bell crank 13 is in the opencircuit position switch 33 is closed, and when the bell crank has movedto substantially the closed circuit position, the limit switch 33 isopened, thereupon deenergizing the motor 29 and pump 5.

In order that the initial starting movement of the operating member 9shall be att-ended by sufficient fluid pressure, the valve 6 is notclosed until the motor 29 has come up to predetermined or normal speedthereby enabling the gear pump to deliver fluid at itsA full ratedcapacity. For this purpose 'the valve 6 is adapted to be closed by anelectromagnet 35 coacting with a magnetiizable core 36 secured to thevalve stem 37. The valve 6 is normally biased towards its open position,as illustrated, by suitable means as a spring 3S seated at its upper endagainst the cover of the reservoir, and bearing at its lower end againsta collar 39 securedr'to the valve stem. Energization of theelectromagnet 35 serves to close the valve`6, and deenergization of theelectromagnet permits the spring 38 to return the valve to its openposition when the piston 9 has reached the end of the stroke and thefluid pressure is reduced by the opening of the ports 11. Energizationand deenergization of the electromagnet may be automatically controlledby a centrifugal switch device 40 secured in any suitable man-A ner tothe rotating structure of the motor 'maman thereby placing theelectromagnet 35 partly under the control of the operator, as where theoperation of the mainy breaker yshould be in accordance with theindication of a synchroscope. 'In the present instance the centrifugalswitch comprises a pair of flyball contacts 41k mounted upon a portionof the rotor shaft and normally biased towards each other by a spring orother suitable means.k Rotation of the rotor shaft servesto force the'free ends of the flyball contacts outwardly towards a collector ring42`connected to a stationary terminal 43.r The other terminal 44 may beconnected to the flyball contacts throughk a slip ring 45. Accordingly,rotation of the motor at a predetermined or normal speed is effective toclose the circuit through the centrifugal switch, thereupon partiallycompleting the circuit so that the closing switch 40 in series may beoperated at the proper time to complete the circuit, energizing theelectromagnet 35 from the source 31 and closing the valve 6.

The operation of the mechanism and associated system may be brieflydescribed as follows:

Assuming the parts of the mechanism to be in the positionsillustrated,`and that it is desired to close the circuit breaker, switch32 is first closed, causing energization vof the motor 29 and pump. Dueto the fact that the actual circuit closing operation is effected withina comparatively short time,ythe operator may readily hold the switch 32closed until the operation is complete.r Or, by closing the switch 32 arelay may be energized for maintaining the motor circuit closed. Initialactuation of the gear pump serves simply to force fluid through thepassager 4 back into the main port of the reservoir through the openvalve 6 and ports 8. That is, the application'of fluid pressure to thepiston is delayed while the pump is discharg ing fluid at a rate lessthan normal. kAs the motor attains its normal speed and the pump isdischarging fluid atfull capacity into the passage 4. the valve 6 may beclosed through the centrifugal switch 40 so that the effect of the fluidpressure within the passage 4, which rapidly increases due tothe factthat the valve 6 is now closed and the pump discharging a substantiallynonfcompressible fluid into the passage 4, causes the piston 9 to moveupwardly at a yrate corresponding to the rate of fluid discharged by thepump. When the closing operation ispcontrolled bv the centrifugalkswitch 40 without the additional control switch 40 in series therewith,the system is applicable to feeder circuits.

In the event that the switch actuating mechanism is acting against largerepellent forces, any tendency on the part of the piston 9 to slow up iscounteracted by the effect of the .lange amoimt of stored energy intheflywheel f 30 to maintain operation` of the'pump 'at uirmstant speed andthereby maintain .a --constantrateof dischargetherefrom. `.As the piston.9i is'lifted touncover thehexhaust ports .1lat which point kthe* switchactuating mech- .anism has been moved to the circuit` closingipositi`on,1the fluidisz byLpassed into the .reservoir and causes nofurther movement of the rpiston.' yAs previously described, the motor129 is deenergized by the limit switch 33 when the toggle 17 has beenstraightened to Vclose `the switch, and in y the event thatv abnormalcircuitconditions are-:present in 'the circuit` yto be "controlled-fthe'tripping magnetr24l -serves to disconnect the hydraulic operating memberfrom the `switch actuating member and to permit immediate openingoftheccircuitfbreaker. i f' f lIt shallbe understoodthat myiinv'entionis4not limited;v to `the specific arrangement and .detailspof constructioninthe embodiment .il- Alustratediand that various changes andmodiyficatio'nswill occur to those skilled inthe art ywithout departingfrom Vthespirit yof my -in- .ventiom L 'f `'VVhatI claim as new;anddesire to secure by Letters Patent of the United Stateszis: 51. Acircuitcontrollingsystem comprising la switchactuatingmember, a fluid operatedmember operatively 'connected with f said switchactuating member,'a'pumpfor effect-V ingmovement of saidfluid operatedmemberto.circuit-closingposition at a rate correspondingtofthe rateof'fluid discharged from the g'pump, afflywheel "for maintaining 'thespeed offsaid pump substantially constant notwithstanding appreciableVforces tending ti'resistclosure` of said'switch actuating mem-' `berrandrnotive meansv deenergizedupon closy,

i'ng movement'o'fl said switchk actuating member'for-actuatirrg saidflywheel. f. n l 2. yAfcircuit controlling system comprising a 1 switchf actuating member, a. fluid operated member, meansoperativelyconnecting said members av pump foreffecting discharge offluid so asfto cause vmovement of the fluid operatedfmember and kcircuitclosing movement ofthe i switch actuating member, a flywheel operativelyconnected'tosaid pump for maintaining discharge ofi'fluid therefromat asubstaintally uniform :,rate, thereby effecting closing `movement of theswitch actuating memberfatja substantially constant or uniform' yratelnotwithstanding forces i opposing such movement, and means delaying theapplication i of r fluid ,pressure to said yfluid operated member`until* said;pump attains norm'a'l speed of operation. 1

3. Arcircuit controlling system. comprising afewitch actuatingfmemberyapiston opera-` tively connectedtherewith, a collapsible connectionbetween said piston and switch actuating menibsfna pump .for dischargingfluid at a rate corresponding tothe speed of the pump for effectingcircuit closing movement of the piston, means causing opening movementof said switch actuating member through said collapsible connection dur-5 ing switch closing movement of said piston, motive means for drivingsaid pump, and a flywheel operatively connected to said motive means andpump for maintaining the rate of fluid discharge from the pumpsubstantially constant notwithstanding forces opposing movement of theswitch actuating member.

4. A circuit controlling system comprising in combination a switchactuatingmember, a fluid operated member, toggle structure operativelyconnecting said members for transmitting closing movement to the switchactuating member, a pump for discharging fluid to cause movement of thefluid operated member, a flywheel operatively connected to said pump formaintaining the rate of fluid discharge therefrom substantiallyconstant, the rate of movement of the fluid operated membercorresponding to said rate of fluid discharge, and means operable toeffect collapse of said toggle structure during closing movement of theswitch actuating member thereby permitting immediate reverse movement ofthe switch actuating member to open position.

5. A circuit controlling system comprising in combination a switchactuating member, a piston operatively connected with said member, apiston operatively connected with said member, a fluid pump fordischarging fluid to cause movement of the piston, the rate of movementof the piston in a switch closing direction corresponding to the rate offluid discharge from the pump, a flywheel operatively connected to saidpump maintaining the rate of fluid discharge therefrom substantiallyconstant and closing the switch against repellent forces, a fluidreservoir in which said pump is immersed, a valve disposed within saidreservoir in communication with the discharge of the pump, andelectromagnetic means controlling said valve for delaying application offluid pressure to the piston until the pump is discharging fluid at apredetermined rate, said electromagnetic means energized in response topredetermined speed of said pump.

6. A circuit controlling system comprising in combination a switchactuating member, a piston opera-tively connected with said member, afluid pump for discharging fluid to cause positive and substantiallyuniform movement of the piston, and speed responsive means for delayingvapplication of fiuid pressure to the piston until the pump isdischarging fluid at a predetermined rate.

In witness whereof I have hereunto set my hand this 21st day ofNovember, 1929.

WILLIAM K. RANKIN.

